The most commonly used polycarbosilane precursor to silicon carbide ceramics is "Nicalon", manufactured by the Nippon Carbon Company. (See S. Yajima, Am. Ceram. Soc. Bul., 62,893 (1982)). "Nicalon" is based on polydimethylsilane [Si(CH.sub.3).sub.2 ].sub.n, a polymer which has a silicon to carbon ratio (Si:C) of 1:2. In order to manufacture ceramic fibers from a ceramic precursor, it must retain its shape during firing. However, to accomplish this with "Nicalon", firing must be carried out in the presence of oxygen which stabilizes the "Nicalon" preceramic.
Silicon carbide ceramics are of growing technical and commercial import because of their use in high technology products. Thus, precursors to silicon carbide and processes for their preparation offer fruitful areas for research. In particular, novel highly crosslinked precursors for ceramic fibers that lead to pure silicon carbide, SiC, and do not need oxygen curing are of great commercial interest.